Versicorin,a new lovastatin analogue from the fungus Aspergillus versicolor SC0156

A new lovastatin analogue versicorin (1), together with three related compounds, decumbenones A (2) and B (3) and versiol (4), were isolated from mycelial solid cultures of Aspergillus versicolor SC0156. Their structures were elucidated on the basis of MS data and NMR spectroscopic analysis. The new compound versicorin (1) possesses a hexahydro-2H-naphtho[1,8-bc]furan moiety, which is a rare type of the lovastatin-analogous compounds. A hypothetical biosynthetic pathway for compounds 1–4 was proposed.     

Novel Chromone Derivatives from Marine Fungus Aspergillus versicolor Isolated from the Sponge Xestospongia exigua

In the continuation of our research for the bioactive secondary metabolites from the sponge-associated fungi, the bioassay guiding fractionation led to the isolation of six new secondary metabolites with unusual skeleton based on chromone ring system from the inoculated fungus Aspergillus versicolor, that had been isolated from fresh samples of marine sponge Xestospongia exigua, collected along coast line of Bali, Indonesia in 1997. The basic skeleton of those compounds possessed an oxohexacy…     

Four Novel Hydropyranoindeno-Derivatives from Marine Fungus Aspergillus versicolor

In the previous report on bioactive secondary metabolites from the sponge-associated fungus Aspergillus versicolor (Vuill) Tirab, the bioassay guiding fractionation led to isolation of six new compounds with unusual skeleton based on chromone ring system from the inculated fungus which was isolated from fresh samples of marine sponge Xestospongia exigua, collected along coast line of Bali, Indonesia in 19971. In the continuation of our chemical investigation on the marine fungus, four compou…     

Antimicrobial activity and molecular docking studies of a novel anthraquinone from a marine-derived fungus Aspergillus versicolor

A novel anthraquinone, 2-(dimethoxymethyl)-1-hydroxyanthracene-9,10-dione (1), together with nine known compounds (2–10), were isolated from the fermentation of Aspergillus versicolor derived from deep sea sediment. Their structures were established through spectroscopic methods. Compound 1 exhibited strong inhibitory activities against MRSA ATCC 43300 and MRSA CGMCC 1.12409 (with MIC values of 3.9 and 7.8 μg/mL respectively) and moderate activities against tested strains of Vibrio (with MIC values ranging from 15.6 to 62.5 μg/mL). Compound 1 was subjected to molecular docking studies for inhibition of topoisomerase IV and AmpC β-lactamase enzymes indicating its usefulness as antimicrobial agent.     

Discovery of a new biphenyl derivative by epigenetic manipulation of marine-derived fungus Aspergillus versicolor

Cultivation of the marine-derived Aspergillus versicolor MCCC 3A00080 with the addition of a histone deacetylase inhibitor, suberoylanilide hydroxamic acid (SAHA), significantly enhanced the diversity of secondary metabolites. From the culture treated, a new biphenyl derivative, named versiperol A (1), along with two known compounds, 2,4-dimethoxyphenol (2) and diorcinol (3) were isolated. The structures of 1–3 were established based on spectroscopic analysis and comparison with literature data. Among the isolates, versiperol A (1) exhibited modest inhibition of Staphylococcus aureus growth with MIC value of 8 μg/mL.     

Two New Cyclic Pentapeptides from the Marine‐Derived Fungus Aspergillus versicolor

Two new cyclic pentapeptides, named versicotides A ( 1 ) and B ( 2 ), were obtained from a marine‐derived fungus strain ZLN‐60, identified as Aspergillus versicolor. Their structures were established on the basis of chemical and spectroscopic evidence. Versicotides are new cyclic pentapeptides which contain an L ‐alanine residue, two anthranilic acid (=2‐aminobenzoic acid) residues, and two N‐methyl‐L ‐alanine residues. Antitumor activities were evaluated by the SRB and MTT methods.     

Three New Chromone Derivatives Produced by Phomopsis sp. HNY29‐2B from Acanthus ilicifolius Linn.

Three new chromone derivatives, phomochromenones A‐C ( 1–3 ), and one known chaetocyclinone B ( 4 ) were obtained from the cultures of Phomopsis sp. HNY29‐2B isolated from the mangrove Acanthus ilicifolius Linn., which was collected from the South China Sea. Their structures were determined by the analysis of ¹D NMR and ²D NMR as well as mass spectroscopic data. The absolute configurations of 1 and 2 were assigned by quantum chemical calculations of the electronic circular dichroism (ECD ) spectra. Compound 3 is the third example of alkaloids possessing the unique chromeno [3,2‐c ] pyridine nucleus. In the bioactivity assay, compound 4 showed cytotoxicity against human prostate cancer cell lines (PC ‐3 and DU145 cells) with the IC₅₀ values of 8.13 and 3.59 µmol/L, respectively.     

Terretonin D1, a new meroterpenoid from marine-derived Aspergillus terreus ML-44

A new meroterpenoid, named terretonin D1 (1), and three known ones, terretonin (2), terretonin A (3), and terretonin D (4), were isolated from marine-derived fungus Aspergillus terreus ML-44. The structure of 1 was elucidated by extensive spectroscopic methods, including 1D and 2D NMR, HR-ESI-MS, and the absolute configuration was determined by X-ray crystallographic analysis. The anti-inflammation activity of 1–4 was preliminarily tested, and all of them weakly inhibited the nitric oxide (NO) production of RAW264.7 macrophages stimulated by lipopolysaccharide (LPS), with inhibitory rates of 22–34% at 50?μg/mL.     

A new sesquiterpene from an endophytic Aspergillus versicolor strain

A new sesquiterpene, albican-1,14-diol (1), and seven known compounds, including sterigmatocystin (2), 3-hydroxy-5-(hydroxymethyl)-4-(4'-hydroxyphenoxy) pyrrolidin-2-one (3), (1H-indol-3-yl) oxoacetamide (4), indole-3-carboxylic acid (5), indole-3-acetic acid (6), indole-3-carboxaldehyde (7), and volemolide (8), were isolated from the cultures of Aspergillus versicolor, an endophytic fungus isolated from the marine green alga Codium fragile. The structure of 1 was elucidated by 1D, 2D NMR and mass spectroscopic techniques. The bioassay results showed that 1 possessed potent activity against brine shrimp, Escherichia coli, and Staphyloccocus aureus.     

Antioxidant coumarin and pyrone derivatives from the insect-associated fungus Aspergillus Versicolor

Abstract

Two new compounds, versicolones A and B (1 and 2), and three known pyrone derivatives (3?5) were isolated from the insect-associated fungus Aspergillus versicolor. Their structures were elucidated through a combination of HRESIMS and NMR spectroscopic analysis. Versicolone A (1) was revealed as a coumarin derivative with the rare 5-alkyl side chain substitution. Compound 5 exhibited significant antioxidant activity with EC₅₀ value of 8.0?μM in the ABTS (2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid) assay, which was more than 2-fold potency of the positive control trolox.     

Xanthones with α‐Glucosidase Inhibitory Activities from Aspergillus versicolor,a Fungal Endophyte of Huperzia serrata

Three new xanthones, namely huperxanthones A–C ( 1 – 3 , resp.), were obtained from the cultures of Aspergillus versicolor, a fungal endophyte of Huperzia serrata, together with 1,7‐dihydroxy‐8‐(methoxycarbonyl)xanthone‐3‐carboxylic acid ( 4 ), β‐diversonolic acid methyl ester ( 5 ), 4‐hydroxyvertixanthone ( 6 ), and sydowinin B ( 7 ). The structures of the new compounds were established by detailed NMR and MS analysis, especially by 2D‐NMR experiments. All xanthones were evaluated for their effects on α‐glucosidase. Compound 4 exhibited a potent inhibitory activity against α‐glucosidase with an IC₅₀ value of 0.24 mM (vs. 0.38 mM for acarbose). The rest of the compounds showed weak or no activity against α‐glucosidase.     

Four New Alkaloids,Brevianamides O – R,from the Fungus Aspergillus versicolor

Four new alkaloids, brevianamides O–R ( 1 – 4 , resp.), were isolated from the AcOEt extract of the solid‐state fermented rice culture of the fungus Aspergillus versicolor. Their structures were elucidated on the basis of spectroscopic analyses.     

A Steroidal Glycoside from Cynanchum versicolor Bunge

Cynanchum versicolor Bunge, one species of the well known Chinese herbal medicine “paiwei”, has been used as an antifebrile and diuretic agent for a long time in China1. Previous phytochemical studies in this species have reported the occurrence of some…     

Enantiomeric resolution,stereochemical assignment and toxicity evaluation of TPA enantiomers

Tetrahydro‐α ‐(1‐methylethyl)‐2‐oxo‐1(2H)‐pyrimidineacetic acid (TPA) is a critical intermediate in the synthesis of HIV protease inhibitors. A simple and efficient method for the separation and determination of TPA enantiomers was developed. The TPA was separated into its enantiomers with an enantiomeric purity of 99% using an HPLC system equipped with a Chiralpak OD‐H column. Semi‐preparative HPLC enantioseparations were carried out for further enrichment of the enantiomers. The validity of this method was evaluated on the basis of its precision, accuracy, linearity and recovery. The method was observed to be suitable for the rapid separation and semi‐preparation of TPA isomers. The separated enantiomers were identified by optical rotation and high‐resolution electrospray ionization mass spectrometry. Furthermore, the stereochemical structures of the TPA enantiomers were definitively confirmed using a combination of experimental and calculated electronic circular dichroism spectra. The toxicity of the separated pure enantiomers against Oryzias melastigma was evaluated using the median lethal concentration (LC₅₀) values. The results indicated that (S )‐(−)‐TPA is ~2.5 times more toxic than its enantiomorphism.     

Determination of Protein Concentration from CD Spectrum

Abstract

Protein concentration can be determined from its circular dichroism(CD) spectrum and from programs that calculate protein secondary structure content from CD. The method established was successfully applied to lysozyme and a de novo designed peptide with a standard error of about 5%, which is comparable to concentrations determined from an estimated extinction coefficient. This procedure is widely applicable in protein and peptide samples.     

Notoamide E: Biosynthetic incorporation into notoamides C and D in cultures of Aspergillus versicolor NRRL 35600

Notoamide E, a short-lived secondary metabolite, has been proposed as a biosynthetic intermediate to several advanced metabolites isolated from Aspergillus versicolor. In order to verify the role of this indole alkaloid along the biosynthetic pathway, synthetic doubly ¹³C-labeled notoamide E was fed to Aspergillus versicolor. Analysis of the metabolites showed significant incorporation of notoamide E into the natural products notoamides C and D.     

Microporotriol,a new cadinane-type sesquiterpenoid from the cultures of the wood-decay fungus Microporus affinis HFG829

Abstract

A new cadinane-type sesquiterpenoid, microporotriol (1), together with four known compound, 5-methylresorcinol (2), (22E,24R)-ergosta-4,6,8(14),22-tetraen-3-one (3), (22E,24R)-ergosta-5,7,22-trien-3β-ol (4), (22E,24R)-5α,8α-epidioxy-ergosta-6,22-dien-3β-ol (5), were isolated from the fermentation broth of the wood decaying fungus Microporus affinis HFG829. The structures of the compounds were established by extensive spectroscopic methods, including 1D & 2D NMR, along with HRMS spectroscopic analysis. The relative configuration of 1 was confirmed by NMR calculation. Compound 1 was evaluated for the cytotoxicity against five human cancer cell lines.     

Isolation and structure determination of a new diketopiperazine dimer from marine-derived fungus Aspergillus sp. SF-5280

A new diketopiperazine dimer designated as SF5280-415 (1) was isolated from an EtOAc extract of the marine-derived fungus Aspergillus sp. SF-5280 by various chromatographic methods. The structure of 1 was mainly determined by analysis of the NMR spectroscopic data and MS data, along with Marfey’s method. This compound is a new diastereoisomer of known bispyrrolidinoindoline diketopiperazine alkaloid WIN 64745, which possesses unique architecture biosynthetically derived from an indole oxidation reaction of tryptophan.     

G‐Quadruplex Secondary Structure Obtained from Circular Dichroism Spectroscopy

A curated library of circular dichroism spectra of 23 G‐quadruplexes of known structure was built and analyzed. The goal of this study was to use this reference library to develop an algorithm to derive quantitative estimates of the secondary structure content of quadruplexes from their experimental CD spectra. Principal component analysis and singular value decomposition were used to characterize the reference spectral library. CD spectra were successfully fit to obtain estimates of the amounts of base steps in anti–anti, syn–anti or anti–syn conformations, in diagonal or lateral loops, or in other conformations. The results show that CD spectra of nucleic acids can be analyzed to obtain quantitative structural information about secondary structure content in an analogous way to methods used to analyze protein CD spectra.     

Phthalimide as a chromophoric tag in the circular dichroism determination of absolute configuration of α-aminoacid amides and dipeptides. A case of a dipeptide isostructurality

Both N-phthaloyl aminoacid amides and methyl amides as well as N-phthaloyl dipeptide methyl esters give Cotton effects of opposite signs at around 220 and 240 nm. The signs of these Cotton effects are directly correlated with the absolute configuration of the N-phthaloyl substituted stereogenic center: for -configuration the Cotton effect at 240 nm is positive and the Cotton effect at 220 is negative. The X-ray analysis shows that the diastereomeric , and , N-phthaloyl alanylvaline methyl esters form isostructural orthorombic crystals due to the conformational flexibility of the molecules and a similar space requirements of the methoxycarbonyl and isopropyl groups.